Tank structure of heat exchanger and method for manufacturing the same

ABSTRACT

A tank structure of a heat exchanger includes a core part having a pair of tubes and fins and a pair of tanks fluidically connected with the tubes. The tank structure includes a tank body formed in a tube shape with at least one corner inside the tank body, the tank body having openings at both end portions thereof, and a pair of end patch plates fixed into the openings to fluid-tightly block off the openings, respectively. The end patch plates are formed to have a thin-walled portion at a position thereof corresponding to the corner of the tank body.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tank structure of a heat exchanger including a core part which has a plurality of tubes and fins and a pair of tanks which is formed to have at least one corner therein and is fluidically connected with the tubes, and also relates to a method for manufacturing the tank structure of the heat exchanger.

2. Description of the Related Art

A conventional tank structure of a heat exchanger for a motor vehicle of this kind is disclosed in Japanese patents laying-open publication No. 2005-83647 and No. 2005-90823. In these conventional tank structures, a pair of tanks is used for flowing cooling medium, such as coolant, therebetween through a core part which is located between the tanks and has a plurality of tubes and fins arranged alternatively with each other. The cooling medium is cooled down by air passing through the core part when it flows through the tubes of the core part connected at their both end portions with the tanks. In the former conventional tank structure, a tank body is formed in a rectangular-tube shape in cross section by folding one aluminum plate, while, in the latter conventional tank structure, a tank body includes two press-formed tank body parts in double-U shape in cross section and a press-formed cover plate having a plurality of loading slots and fixed on the tank body parts, where they are fixed on each other. End patch plates are fitted into two openings at both end portions of the conventional tanks, and the end patch plates and the end portions are brazed to each other.

However, the conventional tank structures of the heat exchangers encounter a problem in that a gap is liable to be formed, especially at a corner formed inside the tank body, between an inner surface of the end portion of the tank body and a fitted-in portion of the end patch plate. The corner is formed by bending a plate to be the tank body, at an overlapped portion of the tank body and at a folded portion thereof. The gap formed at the corner makes it difficult to braze the tank body and the end patch plate firmly and fluid-tightly.

It is, therefore, an object of the present invention to provide a tank structure of a heat exchanger which overcomes the foregoing drawbacks and can decrease a gap formed, at a corner inside a tank body, between the tank body and an end patch plate, and improve fixing strength and liquid-tight ability in brazed portions thereof at the corner.

Another object is to provide a method for manufacturing the tank structure of the heat exchanger which overcomes the foregoing drawbacks.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a tank structure of a heat exchanger which includes a core part having a pair of tubes and fins and a pair of tanks fluidically connected with the tubes. The tank structure includes a tank body formed in a tube shape with at least one corner inside the tank body, the tank body having openings at both end portions thereof, and a pair of end patch plates fixed into the openings to fluid-tightly block off the openings, respectively. The end patch plates are formed to have a thin-walled portion at a position thereof corresponding to the corner of the tank body.

Therefore, the tank structure can decrease the gap formed, at the corner inside the tank body, between the tank body and the end patch plate, and improve fixing strength and liquid-tight ability in brazed portions thereof at the corner.

According to a second aspect of the present invention there is provided method for manufacturing a tank structure of a heat exchanger which includes a core part having a pair of tubes and fins and a pair of tanks fluidically connected with the tubes. The method includes forming the plate into a tank body which has at least one corner inside the tank body, forming the plate into end patch plates to be fixed into opening provided at both end portion of the tank body, respectively, inserting the end patch plates into the openings of the tank body, respectively, deforming a portion, corresponding to the corner of the tank body, of the end patch plates toward the corner to form a thin-walled portion, and brazing the end patch plates and the tank body to each other.

Therefore, the method can decrease the gap formed, at the corner inside the tank body, between the tank body and the end patch plate, and improve fixing strength and liquid-tight ability in brazed portions thereof at the corner.

Preferably, the tank body is formed by using at least one plate, and the corner is formed to have a step of a wall thickness of the at-least one plate by an overlapped portion thereof.

Therefore, the tank structure can be applied to a tank body formed by one plate, which may reduce its manufacturing costs.

Preferably, the end patch plate has a flange portion contactable with an edge portion of the tank body and a projecting portion insertable into the opening of the tank body, the projecting portion including the thin-walled portion.

Therefore, the end patch plate can be manufactured easily and at low costs, and can be easily fitted into the opening of the tank body and be easily deform the projecting portion to have the thin-walled portion.

Preferably, the thin-walled portion is formed by drawing out the projecting portion toward the corner of the tank body.

Therefore, the thin-walled portion can be easily formed by using a jig such as a punch for example.

Preferably, the thin walled portion is formed by clipping the projecting portion so that the projecting portion can cover the step of tank body.

Therefore, the corner such as the step can be easily covered so that the gap generated due to the step is decreased by the thin-walled portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view showing a heat exchanger including a tank structure of an embodiment according to the present invention;

FIG. 2 is a front view showing, the heat exchanger provided with the tank structure of the embodiment shown in FIG. 1;

FIG. 3 is an enlarged perspective view showing a part of a radiator core part, a condenser core part and their tanks of the heat exchanger;

FIG. 4 is a cross sectional view of a tank body of the tank, taken along a line S4-S4 in FIG. 3;

FIG. 5 is an enlarged plan view showing an end patch plate to be fixed to a end portion of the tank body and block off an opening of the tank body;

FIG. 6 is a cross-sectional side view of the end patch plate, taken along a line S6-S6 in FIG. 5;

FIG. 7 is an enlarged cross-sectional view of the tank structure where the tank body and the end patch plate are fixed to each other;

FIG. 8A is a cross-sectional plan view, taken along a line S8-S8, of the tank body and the end patch plate, before brazing process thereof, in a state where the end patch plate is fitted into the opening of the tank body and is not deformed for removing gaps at corners portion of the tank body between the end patch plate and the tank body, and FIG. 8B is a cross-sectional view of the tank body and the end patch plate during and after the brazing process, where the gaps are removed by deforming thin-walled portions of the end patch plate toward the corner portions;

FIG. 9 is an exploded cross-sectional view illustrating how to remove the gaps at the corner portions by deforming the thin-walled portions of the end patch plate; and

FIG. 10 is a perspective view illustrating how cooling mediums flow through a condenser and a radiator of the heat exchanger, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Throughout the following detailed description, similar reference characters and numbers refer to similar elements in all figures of the drawings, and their descriptions are omitted for eliminating duplication.

A tank structure of a preferable embodiment according to the present invention will be described with reference to the accompanying drawings. In the following description, terms “right” and “left” used herein do not correspond to those of the accompanying drawings, but to those with respect to the vehicle body. In addition, a front direction is indicated by “FW” and a rear direction is indicated by “RW” in the drawings.

Referring to FIGS. 1 and 2, there is shown a heat exchanger 1 provided with the tank structure of the embodiment. The heat exchanger 1 is mounted on a front end portion of a not-shown vehicle body of a motor vehicle.

The heat exchanger 1 of the embodiment includes a radiator 2 for cooling a not-shown engine and a condenser 3 of an air-conditioner for cooling a not-shown passenger compartment. The condenser 3 is located at a front side of the radiator 2 and stacked therewith, and a not-shown fan shroud for guiding air flow is located at a rear side of the radiator 2 and fixed thereto.

The radiator 2 has a pair of radiator tanks, consisting of a right side radiator tank 4 and a left side radiator tank 5 which are apart from each other in a lateral direction of the vehicle body, and a radiator core part 6, shown in FIG. 3, located between the right and left side radiator tanks 4 and 5. Incidentally, the radiator core part 6 corresponds to a core part of the present invention, and a right and left side radiator tanks 4 and 5 corresponds to a pair of tanks of the present invention.

The right side radiator tank 4 is provided with a first port P1 projecting rearward from an upper portion thereof, and the left side radiator tank 5 is provided with a second port P2 projecting rearward from a lower portion thereof. The first port P1 is fluidically connected with the engine and the second port P2 is fluidically connected with the engine through a not-shown water pump, so that coolant can circulate between the engine and the radiator 2.

As shown in FIG. 3, the radiator core part 6 has a plurality of tubes 6 a and corrugated fins 6 b. The corrugated fin 6 b is arranged between the adjacent tubes 6 a to promote heat radiation of the coolant flowing through the tubes 6 a through the corrugated fins 6 b. Interiors of tubes 6 a are respectively divided off by partition plates at their central positions in this embodiment.

These tubes 6 a are, what is called, B-type flat tubes, while the tubes 6 a are not limited to this type and may employ other types. In this embodiment, what is called, B type flat tubes are used as the tubes 6 a. The B type flat tube has an oblate cross-section, and its inner space is separated into two parts by a partition portion to each form a passage for flowing coolant. The tubes 6 a are not limited to this type, and other type tubes may be used. The tubes 6 a are fixed at their both end portions to the right and left side tanks 4 and 5 so that the coolant can flow between the tubes 6 a and the right and left side tanks 4 and 5.

On the other hand, the condenser 3 includes a pair of condenser tanks, consisting of a right side condenser tank 3 a and a left side condenser tank 3 b which are apart from each other in the lateral direction, and a condenser core part 3 c located between the right and left side condenser tanks 3 a and 3 b. An interior of the right side condenser tank 3 a is divided at its lower portion by a right partition plate 3 d to define a first room R1 and a fourth room R4, while an interior of the left side condenser tank 3 b is divided at its lower portion by a left partition plate 3 e to define a second room R2 and a third room R3.

As shown in FIG. 2, an inlet port P3 and an outlet port P4 are provided at an upper portion of the right side condenser tank 3 a so that the inlet port P3 is fluidically communicated with the first room R1 and the outlet port P4 is fluidically connected with the fourth room R4 through a first pipe 3 f. The inlet port P3 is fluidically connected with a not-shown compressor, and the outlet port P4 is fluidically connected with a not-shown expansion valve.

A receiver 3 g is fixed to the left side condenser tank 3 b so that it is fluidically connected with the second room R2 and the third room R3 through a second pipe 3 i and a third pipe 3 h, respectively. The condenser core part 3 c has a plurality of tubes 3 j and the corrugated fins 6 b. The corrugated fin 6 b is arranged between the adjacent tubes 3 j to promote heat radiation of refrigerant flowing through the tubes 3 j through the corrugated fins 6 b.

Front portions of the corrugated fins 6 b are used for the condenser 3 and rear portions thereof, integrally connected with the front portions, are used for the radiator 3. The front and rear portions of the corrugated fins 6 b are formed on their vertical surfaces with louvers 6 e as shown in FIG. 3. Configurations, the number and locations of the louvers 6 e may be set arbitrarily, or the louvers 6 e may be removed. In addition, the corrugated fins 6 b may be separated from each other to be independently used for the radiator 2 and for the condenser 3.

As shown in FIGS. 1 and 2, the right and left side radiator tanks 4 and 5 and the right and left side condenser tanks 3 a and 3 b are connected at their upper portions and lower portions by an upper reinforcement beam 6 c and a lower reinforcement beam 6 d, whose both end portions are inserted into and fixed to the tanks 4, 5, 3 a and 3 b.

Next the tank structure of the radiator 2 will be described with reference to the accompanying drawings.

The right side radiator tank 4 and the left side radiator tank 5 are constructed in a bilaterally symmetric relationship with each other, and accordingly only the right side radiator tank 4 will be described and a description of the left side radiator tank 5 will be omitted.

As shown in FIGS. 1 to 3, the right side radiator tank 4 has a tank body 7 and a pair of end patch plates 8 for blocking off upper and lower openings of the tank body 7.

As shown in FIG. 4, the tank body 7 consists of a first tank body part 10 and a second tank body part 11, which are coupled with each other to form in a rectangular tube-like shape with four round corners, a first corner C1 to a fourth corner C4. The first tank body part 10 is made of aluminum plate, and is formed by press-forming to have a main wall portion 10 a and two side wall portions 10 b and 10 c vertically bent from both end portion of the main wall portion 10 a.

The second tank body part 11 is made of aluminum plate, and is formed by press-forming to have a main wall portion 11 a and two side wall portions 11 b and 11 c vertically bent from both end portion of the main wall portion 11 a to be arranged in parallel to the main wall portion 10 a of the first tank body part 10. The side wall portions 11 b and 11 c is set longer than the side wall portions 10 b and 10 c. The side wall portions 11 b and 11 c have two end wall portions 11 d and 11 e vertically bent therefrom to be in parallel to the main wall portion 11 a, respectively, so that the end wall portion 11 d and 11 e and their adjacent portions of the side wall portions 11 b and 11 c of the second tank body part 11 can contact with inner surfaces of the side wall portions 10 b and 10 c and their adjacent portions of the main wall portion 10 a. The end wall portions 11 d and 11 e are not indispensable. The side wall portion 11 c is formed with first through-holes 12 a for fixing the end portions of the reinforcement beams 6 c and 6 d and second through-holes 12 b for fixing the end portions of the tubes 6 a as shown in FIG. 7.

Thus-constructed tank body 7 has two openings at its top position and bottom position, and two end patch plates 8 is fixed into the openings, respectively. In addition, two edges 11 f and 11 g of the both end wall portions 11 d and 11 e project inwardly by a thickness thereof from the inner surface of the main wall portion 10 a of the first tank body part 10, where the edges 11 f and 11 g form two steps, also corresponding to corners of the invention, inside the tank body 7.

As shown in FIGS. 5 and 6, the end patch plate 8 is formed in a rectangular shape and has a flange portion 8 a shaped like a rectangular at its outer peripheral position and a projecting portion 8 b vertically projecting from and surrounded by the flange portion 8 a. The projecting portion 8 b is provided with two slanted portions 8 c and 8 d and an expanded portion 8 e sandwiched between the slanted portions 8 c and 8 d. Note that the slanted portions 8 c and 8 d are formed at positions corresponding to the first corner C1 and the fourth corner C4 of the tank body 7, respectively. As a result, the projecting portion 8 b can be easily fitted into the opening of the tank body 7.

The end patch plates 8 are inserted into the openings of the tank body 7 as shown in FIG. 7, and are deformed to fit more tightly to the openings and then fixed by brazing, which will be later described in detail.

All parts, including the tank structure and the core parts 6 and 3 c of the heat exchanger 1 is made of alminum, and are assembled and brazed.

The heat exchanger 1 of the embodiment is manufactured as follows.

Aluminum plates are prepared and are pressed to form the parts of the heat exchanger 1. Then these parts are temporally assembled.

In this assembly process, the first tank body part 10 and the second tank body part 11 are coupled with each other to form the tank body 7, and, the end patch plates 8 are inserted into the upper and the lower openings of the tank body 7 with the flange portions 8 a being contacted with edge portions of the tank body 7 and outer peripheral portions of the projecting portions 8 b being contacted with inner surfaces of the end portions of the tank body 7.

As shown in FIG. 8A, in a state where the projecting portions 8 b of the end patch plates 8 are inserted into the openings of the tank body 7, larger gaps are certainly generated at the edges 11 f and 11 g of the second tank body part 11, and smaller gaps may be generated at the first to fourth corners C1 to C4 thereof.

Then, as shown in FIG. 8B, four corner portions of the projecting portion 8 b are respectively drawn out outwardly toward the corners C1 to C4 of the second tank body part 11 by using a jig such as punch, so as to be deformed and form four thin-walled portions 9 a to 9 d thereof, removing the gaps formed at the corners C1 to C4.

Next, also as shown in FIG. 8B, the slanted portions 8 c and 8 d are deformed by clipping them by using a jig to form two thin-walled portions 9 e and 9 f so that the deformed slanted portions 8 c and 8 d can cover and tightly contact with the edges 11 f and 11 g of the end portions 11 d and 11 e of the second tank body part 11, removing the gaps formed at the edges 11 f and 11 g.

All the parts are temporally assembled with one-side parts of their joining parts being provided with cladding layer, namely brazing sheet, made of brazing filler metal, and placed into a not-shown heating furnace to be heated so that the joining parts can be brazed to each other.

In this heating process, the thin-walled portions 9 a to 9 d of the end patch plates 8 respectively deform toward the first to fourth corners C1 to C4 due to heat and residual stress caused by the punch, which decreases the gaps and accordingly enhances liquid-tight and strong joining of the parts by brazing.

Similarly, the thin-walled portions 9 e and 9 f of the end patch plates 8 respectively deform toward the edges 11 f and 11 g of the second tank body 11 due to heat and residual stress caused by the jig, where the residual stress at acts in a direction indicated by an arrow AW in FIG. 9. FIG. 9A illustrates only a first corner C1 side of the tank structure, which is bilaterally symmetric with a fourth corner C4 side thereof. Therefore, the thin-walled portions 9 e and 9 f also decreases the gaps and accordingly enhance liquid-tight and strong joining of the parts by brazing.

The operation of the heat exchanger 1 with the tank structure of the embodiment will be described.

In the heat exchanger 1 of the embodiment, as shown in FIG. 10, the hot coolant X flows from an engine side into the right side radiator tank 4 through the first port P1, and is cooled down because of heat transfer through the corrugated fins 6 b between the coolant X and the air flow, caused when vehicle running and/or generated by a fan, while the coolant X flows through the tubes 6 b connecting the right and left side radiator tanks 4 and 5 as indicated by an alternate long and short dash arrow. It is discharged from the left side radiator tank 5 toward the engine through the second port P2.

On the other hand, the hot refrigerant Y flows from an air-conditioner side into the right side condenser tank 3 a the first room R1 of the through the inlet port P3 shown in FIG. 2 and is cooled down because of heat transfer through the corrugated fins 6 b between the refrigerant Y and the air flow, caused when the vehicle running and/or generated by the fan, while the refrigerant Y flows through the tubes 6 b connecting the first and second rooms R1 and R2 as indicated by an alternate long and short dash arrow. Then, the cooled refrigerant Y is introduced into the receiver 3 g through the pipe 3 i for vapor-liquid separation thereof, and then is outputted into the third room R3 through the pipe 3 h. The refrigerant Y travels through the tubes 6 a connecting the third and fourth rooms R3 and R4, and is further cooled down. It is discharged from the left side condenser tank 3 b toward the air-conditioner side through the outlet port P4.

The heat exchanger 1 with the tank structure of the embodiment has the following advantages.

The thin-walled portions 9 a to 9 f can be deformed to decrease the gaps formed, at the corners C1 to C4 and the corners corresponding the edges 11 f and 11 g of the second tank body part 11, between the end patch plates 8 and the tank body 7.

Accordingly, desirable brazing can be carried out between the end patch plates 8 and the tank body 7, thereby enhancing liquid-tight and strong joining of the parts thereof by brazing.

While there have been particularly shown and described with reference to preferred embodiments thereof, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

For example, the heat exchanger of the invention may be only one of a radiator, a condenser and a general heat exchanger, although the heat exchanger 1 of the above-described embodiment has the radiator 2 and the condenser 3 which are integrally assembled with each other.

The tank body of the invention may be formed by using only one aluminum plate, although two plates, namely the first and second tank body parts 10 and 11 are used in the embodiment.

Configuration of the tank body 7 may be set arbitrarily as long as it has at least one corner therein. Configuration of the end patch plate 8 may be set arbitrarily according to that of the tank body 7.

The entire contents of Japanese Patent Application No. 2006-120315 filed Apr. 25, 2006 are incorporated herein by reference. 

1. A tank structure of a heat exchanger which includes a core part having a pair of tubes and fins and a pair of tanks fluidically connected with the tubes, the tank structure comprising: a tank body formed in a tube shape with at least one corner inside the tank body, the tank body having openings at both end portions thereof; and a pair of end patch plates fixed into the openings to fluid-tightly block off the openings, respectively, wherein the end patch plates are formed to have a thin-walled portion at a position thereof corresponding to the corner of the tank body.
 2. The tank structure according to claim 1, wherein the tank body is formed by using at least one plate, and the corner is formed to have a step of a wall thickness of the at-least one plate by an overlapped portion thereof.
 3. The tank structure according to claim 2, wherein the end patch plate has a flange portion contactable with an edge portion of the tank body and a projecting portion insertable into the opening of the tank body, the projecting portion including the thin-walled portion.
 4. The tank structure according to claim 3, wherein the thin-walled portion is formed by drawing out the projecting portion toward the corner of the tank body.
 5. The tank structure according, to claim 4, wherein the thin walled portion is formed by clipping the projecting portion so that the projecting portion can cover the step of tank body.
 6. The tank structure according to claim 1, wherein the end patch plate has a flange portion contactable with an edge portion of the tank body and a projecting portion insertable into the opening of the tank body, the projecting portion including the thin-walled portion.
 7. The tank structure according to claim 6, wherein the thin-walled portion is formed by drawing out the projecting portion toward the corner of the tank body.
 8. The tank structure according to claim 7, wherein the thin walled portion is formed by clipping the projecting portion so that the projecting portion can cover the step of tank body.
 9. A method for manufacturing a tank structure of a heat exchanger which includes a core part having a pair of tubes and fins and a pair of tanks fluidically connected with the tubes, the method comprising: forming the plate into a tank body which has at least one corner inside the tank body; forming the plate into end patch plates to be fixed into opening provided at both end portion of the tank body, respectively; inserting the end patch plates into the openings of the tank body, respectively; deforming a portion, corresponding to the corner of the tank body, of the end patch plates toward the corner to form a thin-walled portion; and brazing the end patch plates and the tank body to each other.
 10. The tank structure according to claim 9, wherein the tank body is formed by using at least one plate, and the corner is formed to have a step of a wall thickness of the at-least one plate by an overlapped portion thereof.
 11. The tank structure according to claim 10, wherein the end patch plate has a flange portion contactable with an edge portion of the tank body and a projecting portion insertable into the opening of the tank body, the projecting portion including the thin-walled portion.
 12. The tank structure according to claim 11, wherein the thin-walled portion is formed by drawing out the projecting portion toward the corner of the tank body.
 13. The tank structure according to claim 12, wherein the thin walled portion is formed by clipping the projecting portion so that the projecting portion can cover the step of tank body. 